TEXAS AGRICULTURAL EXPERIMENT STATION C. H. McDOWELL, ACTING DIRECTOR, College Station, Texas BULLETIN 679 APRIL 1946 THE JEEP AS A SOURCE OF POWER AND TRANS- PORTATION ON FARMS AND RANCHES IN TEXAS H. P. Smith, Chief Division of Agricultural Engineering AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS GIBB GILCHRIST, President D58-646-6M-L180 Fig. 1. Ex- periment Station, December 4, 1944. Bottom-The Universal jeep used in tests by the Texas Agricultural Experiment Station, which was delivered April 5, 1945. T0p—The military jeep at the time of delivery to the Texas Agricultural ~. are.» @- Hundreds of ideas have been suggested as to the possible use of the jeep as a peacetime vehicle in all phases of agriculture. Many of these suggestions are practical, while others are not. The manufacturer, pro- spective buyers, and othe-rs realize that there is a wide range of adapt- ability to agricultural uses, and that there are certain limitations to the i _'ee "s overall use as a source of power and trans rtation in relation to l P agriculture. Consequently, a military jeep and a peacetime Universal jeep were tested during 1945 to determine their adaptability as a source of power and transportation on the farms and ranches in Texas. This bulletin reports the results of these tests. Both models of jeeps were capable of pulling loads, exerting drawbar pulls of 900 to 1200 pounds under many different field and road conditions. The peacetime jeep, because of gear ratio reductions, could pull heavier loads than the military jeep. The peacetime Universal jeep, when equipped with spring seat cushions, side curtains and doors, governor, drawbar, power take-off and pulley, is more comfortable a.nd more adaptable to general farming and ranching operations than the military jeep which is not equipped with these ac- cessories. The jeep is adaptable for pulling light-draft broadcast tools such as harrows, land rollers, rotary hoes, grain drills, hay rakes and other similar implements. The jeep is not adaptable as a source of power for pulling row-crop implements such as planters and cultivators. For general field work the jeep does not compare favorably. with the tractor as a source of power with respect to maneuverability, fuel con- sumption and the handling of implements. As a truck, the jeep provides an excellent source of power for pulling trailers and for hauling produce from farm to market and supplies to the l‘ farm, and for odd jobs about the farm, but it does not compare favorably in capacity to the pick-up truck for hauling. As an automobile, the comforts of the jeep do not compare favorably _ with those of an automobile. - The jeep, however, is an excellent vehicle for general utility use about i the farm and ranch. CONTENTS 9 r Page Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . .. 5 Comparative Specifications of Universal and Military Jeeps . . . . . . . . .. 5 Suggested Uses for the Jeep on Farms and Ranches . . . . . . . . . . . . . . . . . . 8 Gear Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Take-off and Vehicle Speeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Governor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 Hitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Field Maneuverability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13 i Cooling Syste-m of Jeep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14 ‘ Fuel Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14 The Jeep as a Tractor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18 The Jeep as -a Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29 ; The Jeep as an Automobile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 The Jeep as a General Utility Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 31 ' Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34 Summary and Conclusions . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34 a BULLETIN 679 APRIL 1946 THE JEEP AS A SOURCE OF POWER AND TRANSPORTA- TION ON FARMS AND RANCHES IN TEXAS H. P. Smith, Chief Division of Agricultural Engineering There have been hundreds of ideas suggested as to the possible use of the jeep as a peacetime vehicle in all phases of agriculture. Many of these suggestions are practical, while others are not. The manufacturer, prospective buyers, and others realize that there is a wide range of adapt- ability to agricultural uses, and there are certain limitations to its overall use as a source of power and transportation in relation to agriculture. The best way to determine the usefulness of the vehicle is to test it under actual operational conditions. For this reason, the War Food Administration arranged with the Army for the release of a few military jeeps for experimental purposes, one of which was assigned to the Texas Agricultural Experiment Station. This military jeep was overhauled and put in good condition by the Willys-Overland Motors, Inc., and was delivered by them to the Texas Station on December 4, 1944 (Fig. 1—top). As the military jeep was designed to meet military requirements, and it was known that certain changes would make it more suitable for agri- cultural operations, the Willys-Overland Motors, Inc., developed the “Uni- versal jeep” styled and equipped with accessories that would aid in making the vehicle more adaptable and serviceable for the farm and ranch (Fig. "1—bottom). One of these new Universal jeeps was delivered to the Texas Agricultural Experiment Station on April 5, 1945. Therefore, both jeeps were tested as to their adaptability as a source of power and transportation during 1945. This bulletin reports the results. of these tests. Comparative Specifications of the Universal and Military Jeeps The following specifications were taken from data furnished by the Willys-Overland Motors, Inc.: General: The chassis for both the military and Universal jeeps is a four-wheel unit of the four-wheel drive type with an 80-inch wheel base and front wheel steering. The track or tread is 48% inches from center to center of the tires. Universal Military Turning radius . . . . . . . . . . . . . . . . . . . .Right 18 ft. Right 18 ft. Turning radius . . . . . . . . . . . . . . . . . . ..Left 18 ft. Left 18 ft. Overall length (to rear of body)....122‘$é in. 132% in. 6 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION Overall width . . . . . . . . . . . . . . . . . . . .. 59 in. 62 in. _ Overall height—top up . . . . . . . . . . . .. 69 in. 69%, in. Overall height—top down . . . . . . . . . .. 52% in. _ 51% in. Track or tread . . . . . . . . . . . . . . . . . . . .. 481,4 in. 48% in. Road clearance at axles . . . . . . . . . . .. 8% in. 8% in. Road clearance at vehicle center. .. . 9% in. 10-3/32 in. Performance: The maximum weights, loads and speeds are as follows: - Universal Military Maximum gross vehicle weight . . . . . . . . ..3420 lbs. 3250 lbs. Maximum pay load . . . . . . . . . . . . . . . . . . . .. 800 lbs. 800 lbs. Maximum recommended road speed . . . . .. 60 MPH 60 MPH Maximum trailer weight (highway use). .5500 lbs. 3500 lbs. Maximum recommended drawbar pull. . . .1200 lbs. 900 lbs. Frame: Same for both jeeps except for minor details and reinforce- ments of rear end for Universal jeep. The drawbar on the Universal jeep is extra. l Cross Members: Same for both jeeps. Shock Absorbers: Same for both jeeps except for mounting and extended length. of rear units. Springs: Same for both jeeps. Front Aocle-Spicer M0del—25: Same for both jeeps except gear ratio and steering bell crank. Rear Aocle—Spicer Model—25’-2: Same for both jeeps except for gear ratio. Hypoiol Difierentwl: Universal, 5.38 to 1 ratio; Military, 4.88 to 1 ratio. Propeller Shaft: Same for both jeeps. Clutch: Capacity of clutch on Universal jeep is 34 percent greater than ‘clutch on military jeep. Transmissions-Warner Model—T-90A: Approximately 1A; in. wider gear tooth contacts and different gear ratio as follows: Ratio Universal Military 1st . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..2.798 to 1 2.665 to 1 2nd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..1.551 to 1 1.564 to 1 3rd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..1.000 to 1 1.000 to 1 Reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3.780 to 1 3.554 to 1 Transfer Case: Universal jeep same as military jeep except gear ratio is 1.97. The case has separate control handles, located in the center of driver’s compartment, one lever for shifting of low range gear, and one lever for shifting the declutching mechanism for the front wheel drive and is designed so as to prevent low range gearing being utilized when front axle drive is disengaged. THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 7 Hand Brake: Universal jeep same as latest model military jeep. Service Brakes: Both jeeps are equipped with internal expanding hy- draulic brakes operating on all four wheels. Engine: Same for both jeeps, except Universal jeep has different car- buretor throttle. Specifications of the engine for Universal jeep are as follows: Type—gasoline-—“L” head Number of cylinders—4 Bore-—3% in. Stroke—4% in. Displacement—134.2 cu. in. Compression ratio—6.48 to 1 Horsepower: SAE rating—15.6 Actua1—60 at 4000 R.P.M. Other Features: Minor changes between the military jeep and the Universal jeep have been made in muffler arrangement, radiator shroud- ing, steering bell crank, electrical equipment to meet civilian require- ments, and instruments, such as, speedometer and gasoline and oil gauges. Lighting equipment has been changed to meet legal requirements of state laws. The Universal jeep is equipped with drop center wheels carrying 6.00x16 four-ply tires. Optional Accessories and Equipment: A variable speed governor can be obtained having 9 positions of control. A power take-off shaft, and pulley drive are available for operating extra equipment. The shaft turns at 536 R.P.M. in a clockwise direction when viewed from the rear, and delivers to the implement approximately 25 H.P. at a road speed- of l approximately 4.2 MPH, or 17 H.P. at 2.9 MPH. The 8 in. pulley drive is attached to the power take-off shaft and will furnish 30 H.P. at a belt i speed of 3100 feet per minute. Extra Weights are provided to maintain good traction of front wheels when pulling heavy loads. These weights can be used on either the Universal or military models. Table l. Maximum Road Speeds ‘ Transfer case in Transmission in High range Low range é Universal Military Universal Military F g: High . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 65 24 33 F Intermediate . . . . . . . . . . . . . . . . . . . . . . 38 41 16 21 Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 24 9 12 éReverse . . . . . . . . . . . . . . . . . . . . . . . . . . 16 18 6 9 Capacities of Various Units: The capacities of the fuel tank, engine E 8 BULLETIN NO. 679. TEXAS AGRICULTURAL EXPERIMENT STATION crank case, radiator and various other units for the Universal and military jeeps are as follows: Universal Military Fuel tank (gallons) . . . . . . . . . . . . . . . . . . . . . . . . . .10.50 15.00 Engine crank case refill (quarts) . . . . . . . . . . . .. 4.00 4.00 Cooling system (quarts) . . . . . . . . . . . . . . . . . . . ..11.00 11.00 Transmission (pints) . . . . . . . . . . . . . . . . . . . . . .. 1.50 1.50 Transfer case (pints) . . . . . . . . . . . . . . . . . . . . . . .. 3.00 3.00 Front axle differential (pints) . . . . . . . . . . . . . . .. 2.50 2.50 Rear axle differential (pints) . . . . . . . . . . . . . . .. 2.50 2.50 Front axle steering knuckle bearings (pounds) .50 .50 Oil bath air cleaner (pints) . . . . . . . . . . . . . . . . .. 1.25 1.25 Brake system brake fluid (pints) . . . . . . . . . . . .. .75 .75 Suggested Uses for the Jeep on Farms and Ranches Many uses for the jeep have been suggested such as follows: 1. Manure spreading 2. Plowing 3. Harrowing with disk, spring and spike tooth harrows 4. Land rolling 5. Seeding—drill and broadcast 6 7 8 9 Cultivating—rotary hoe Plant thinning—cotton and beets Spraying l . Harvesting—binders, grain and row, combines 10. Transfer of implements, barn to field and field to field l 11. Pulling trailers 12. Wire stretching 13. Inspection and repair of fences 14. Feed hauling 15. Water hauling 16. Milk delivery (bulk) 17. Pumping 18. Operating of small portable saw mill 19. Grinding 20. Operation of thresher 21. Operation of corn cutter 22. Filling silos 23. Pulling stone boat or sled 24. Fire fighting—community or forestry 25. Inspection of livestock on range 26. Removal of sick or dead livestock 27. Logging 28. Transporting of labor 29. Brush clearing 30. General utility vehicle THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION u Gear Ratios The military jeep was designed to give adequate speeds and maneuver- ability for military purposes with no thought of the vehicle later being used as a source of power for the farm. Consequently, the gear ratios are such that slow rates of travel necessary to operate some farm tools cannot be obtained without throttling down the engine. When this is done, engine horse power is reduced to a point that the tool cannot always be i operated efiiciently. In developing the Universal jeep different gear ratios were used to give more power at slower rates of travel. In the transmission, wider gears, improved lubrication and larger bearings were included in the improve- ments. The transmission has three forward gear ratios with 1 to 1 in high, 1.55 to 1 in intermediate, and 2.8 to 1 in low gear. The gear reduction was increased somewhat to arrive at a lower road speed for the same engine speed. For the same reason, the transfer case ratio reduction was increased almost 25 percent and is 2.43 to 1. The last units in the power transmission are the axles. Similar to the increase in reduction in the transmission and transfer case, the axle ratio was changed from 4.88 to 5.38. The road speeds obtained with these ratio and maximum engine speeds are shown in Table 1. Power Take-off and Vehicle Speeds To satisfactorily operate many machines, the ‘operator should know the speed of the power take-off shaft or the belt pulley as well as the vehicle ground speed. A great variety of speeds are made available by the manual governor control, the gear ratios in the transmission and transfer case and by interchanging the gears in the power take-off housing. Tables 2 and 3 indicate the speeds for each of the nine positions of the manual governor control. Note that the shaft speeds are all computed with the vehicle in four Wheel drive, and that of the belt pulley in the transmission drive only. Reference to these tables will be of material assistance in the operation of much equipment especially the farm combine or grain separator. Table 2. Power Take-ofl‘ Shaft Speeds (R.P.M.) and Vehicle Ground Speeds (M.P.H.) Power Take-oh’ Gear Ratios OI‘ 20-24 RATIO 24—20 RATIO G Transmission Gear In Transmission Gear In ov- ernor Transfer Low Inter. High Low Inter. High Engine Control In _ Speed Positions Take-off Vehicle Take-off Vehicle Take-off Vehicle Take-off Vehicle Take-oil Vehicle Take-off Vehicle Shaft S peed Shaft S peed Shaft S peed Shaft S peed Shaft S peed Shaft Speed R.P.M. M.P.H. R.P.M. M.P.H. R.P.M. M.P.H. R.P.M. M.P.H. R.P.M. M.P.H. R.P.M. M.P.H.‘ Low 298 2 .22 537 4 .01 833 6.22 428 2 .22 773 4.01 1200 6.22 1 High 298 5 .40 537 9 .75 833 15.13 428 5 .40 773 9.75 1200 15.13 1000 Low 357 2 .67 644 4 .81 1000 7.47 514 2 .67 928 4 .81 1440 7 .47 2 High 357 6.48 644 11.71 1000 18.15 514 6.48 928 11.71 1440 18.15 1200 Low 417 3.11 752 5.62 1166 8.72 600 3.11 1083 5.62 1680 8.72 3 High 417 7.56 752 13.66 1166 21.17 600 7.56 1083 13.66 1680 21.17 1400 Low 476 3 .56 859 6 .42 1333 9 .96 685 3.56 1237 6.42 1920 9.96 4 High 476 8.65 859 15 .61 1333 24.20 685 8 .65 1237 15.61 1920 24 .20 1600 Low 536 4.00 967 7.22 1500 12 .08 771 4 .00 1392 7.22 2160 12.08 5 High 536 9. 73 967 17.56 1500 27.22 771 9 .73 1392 17.56 2160 27.22 1800 Low 595 4 .44 _ 1074 8.02 1666 12 .45 857 4.44 1547 8 .02 2400 12.45 6 High 595 10.81 1074 19.51 1666 30 .25 857 10.81 1547 19 .51 2400 30.25 2000 Low 655 4 . 89 1182 8.83 1833 13.70 942 4.89 1702 8.83 2640 13 .70 7 High 655 11 .89 1182 21 .46 1 833 33 .27 942 11 . 89 1 702 21 . 46 2640 33.27 2200 Low 714 5 .34 1289 9 .63 2000 14.94 1028 5 .34 1856 9 .63 2880 14.94 8 High 714 12.97 1289 23 .41 2000 36 .31 1028 12 .97 1856 23 .41 2880 36.31 2400 Low 774 5.78 1396 10.43 2166 16.19 1114 5.78“ 2011 10.43 3120 16.19 9 High 774 14.05 1396 25.36 2166 39.33 1114 14.05 2011 25.36 3120 39.33 2600 ‘4QLAui_J.44J.»_ . .4. . NOLLVLS LNEINIHEIdXEI TVHIIJIIIIOIIIDV SVXELL '6L9 ‘ON NILEITIHEI THE JEEP AS A SOURCE‘ OF POWER AND TRANSPORTATION 11 Table 3. Pulley Speeds (R. P. M.)——8-in. Pulley. Power Take-ofl’ Gear Ratios 8 20-24 24-20 iGovernor _ _ _ ' ’ _ _ _ 1 Control Transmission Gear 1n Transmission Gear 1n Engine i Positions _ _ S peeds " ~ Low Inter. High Low Inter. High . 1 255 460 " 714 367 663 1028 1000 i 2 306 552 857 440 795 1234 1200 3 357 645 1000 514 928 1440 1400 p. 4 408 737 1 143 587 1061 1645 1 600 “ 5 459 - 829 1285 660 1193 1851 1800 ‘ 6 510 921 1428 734 1326 2057 2000 " 7 561 1013 1571 807 ~‘ 1458 2262 2200 < 8 612 1105 1714 ' 881 1591 2468 2400 .» 9 663 1197 1857 954 1723 2674 2600 Governor From the discussion under gear ratios, power take-off and vehicle speeds "is seen that the governor plays an important role, as indicated in Tables v 3 and 4. The governor has nine positions of control. By setting the 'vernor and the throttle most any desired engine speed may be obtained. v erally the governor is used only for field ~and belt work, where uniform ormance is needed, but if desired it can also be used for limiting the d on the highway. V >7\ ' ‘The military jeep was not equipped with a governor and all controls Q e manipulated manually. This requires close attention on the part of F’ operator. a . e 4. Efiect ol‘ Governor on Speed of Universal Jeep in Low Transmission and Transfer ‘ Cases _ _ Engine speed Vehicle slpeed Governor control position _ (R. P. M.) (M. P. .) V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1000 2.2 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1200 2.6 ;; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . _ . . . . .. 1400 3,1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . .. 1600 3.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1800 4.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2000 4.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2200 %.s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2400 .2 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . .. 2600 5.7 Clearance :R0ad clearance at the axles is 8% inches for bothhthe rmilitary and $1 iversal jeeps. At the center of the vehicle theevvroavd clearance for the itary jeep is 10-3/32 inches and 9% inches for the Universal jeep. {For the average ‘lfarm and ranch operations these clearances appear to. 12 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION be adequate. In all the operations "performed with each of these vehicles no trouble was encountered from lack of clearance. Hitch When the military jeep was delivered it was equipped with standard ‘military bumpers and trailer hitch. This type of hitch could not be used with typical farm pin and ball trailer hitches. The vehicle was not equipped with a drawbar so that farm tools, such as plows, harrows and the like, could. be attached. Therefore, the regular rear bumpers, bracket for auxiliary gas tank, and military trailer hitch were removed and a drawbar 28 inches in length and 15 inches from the ground was placed on the jeep as shown in Fig. 2. A trailer hitch for use of a pin or ball such as used on the average farm was substituted for the military type hitch. This hitch was 22 inches above the ground as shown in Fig. 2. Fig. 2. Drawbar and trailer hitches mounted on military jeep. Either a ball or pin can be used with the trailer hitch. Later it was found that for some tools the drawbar should extend the full width of the vehicle. Smith‘and Trenaryl found that when heavy loads were hooked to the regular trailer hitch, 22 inches in height, the weight on the front wheels was decreased as the load was increased. The lower drawbar hitch and weight on the front bumper of the Uni- versal jeep enables the front wheels to have good traction. The weights and low drawbar can be used on the military jeep. 1L. J. Smith and O. J. Trenary, The Jeep as a Farm Truck-Tractor for the Post War Period, Washington Agricultural Experiment Station, Bulletin 455, May 1944. THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 13 A two-row tractor type stalk cutter was hitched to- the military jeep as far to one end of the drawbar as possible so that the jeep could be made to straddle one row of stalks and at the same time shift the stalk cutter to the side far enough so that two rows of stalks could be cut. With the 28-inch drawbar the jeep could not be driven centered over the row but had to be driven to one side (Fig. 3—left). When pulling a four- row stalk cutter the jeep had to be driven with the wheels on each side running on a row of stalks or stubble (Fig. 3—-right). Fig. 3. Left—Military jeep pulling a two-row tractor type stalk cutter cutting cotter stalks. The cutter is hitched to the left end of the drawbar and the left wheels of the jeep are almost running on the row of stalks. Right—The Universal jee-p pulling a four-row homemade stalk cutter cutting sorghum stubble. The cutter is hitched to the center of the drawbar of the jeep, thus making it necessary to drive with the wheels running directly on the two center rows. A longer drawbar would also be useful in towing implements over the highway as the jeep then could be hitched so that it would not extend out into the highway more than the implement. Heavy loads hitched to the extreme side would cause excessive side draft. Field Maneuverability The usefulness of any source of power for the operation of field imple- . ments depends to a large extent on its maneuverability. The turning radius of both jeep models with no load on pavement or firm ground is 18 feet. If the ground is soft, such as plowed ground, the turning radius is affected and the radius is increased. The effect will be less if the vehicle is in four-wheel drive. Even the minimum turning radius of 18 feet or a circle 36 feet in . diameter creates a handicap when handling row-crop machinery. A wide headland is required to permit the trailing implement to clear the end of the row, then swing around and become lined up with the rows for the next trip across the field. Under ordinary cropping conditions the headlands at the ends of the rows are not wide enough for such turning > and, as a consequence, several feet of crop row may be damaged at each end. 14 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION The auto steering does not permit quick enough turns for maneuvering machines such as binders to maintain square corners in the harvesting operation. When plowing an irregular shaped field and using a jeep for power, it is necessary at each corner to continue straight ahead until the plow reaches the corner, then steer the jeep sharply to the left for several feet, then swing back to the right, pass the corner, then continue steering to the right to bring the plow in line with the furrow. Such a maneuver would require making a complete circle of several feet over the plowed ground which would be well packed after a few turns over it. Therefore, when plowing and using a jeep for power it would be best to plow by lands and do the turning at the ends across the headland. On the other hand, when a jeep is used to pull a disk harrow, spike tooth or spring tooth harrow where overlapping or even turning is not required, the jeep can maneuver the turns satisfactorily. Cooling System of Jeep The capacity of the cooling system of the jeep is 11 quarts, or 1 quart less than 3 gallons. Under ordinary road driving, light loads and summer weather conditions of Texas the engine will operate at approximately A175 to 180 degrees F. However, it was found that when the atmospheric temperature rose to 90 to 95 degrees F. or higher, and loads above 600 pounds drawbar pull were used, the temperature of the engine ranged higher than 180 degrees F. If capacity loads were pulled the engine overheated. The military jeep is equipped with a four-blade fan and the radiator is not shrouded and, as a consequence, the engine of this jeep had a tendency to run hotter than the Universal jeep which is equipped with a six-blade fan and the radiator is shrouded. Trash collecting on the screen in front of the radiator will reduce air flow through the radiator and affect the cooling of the engine. When doing stationary belt work, such as operating a feed mill or silage cutter, the temperature of the engine can be held down 6 to 8 degrees by raising the hood. Fuel Consumption From December 4, 1944, to December 31, 1945, the military jeep was driven a total of 6,257 miles for all operations performed in the field, on ranches, as a general utility vehicle about the farm and over the highway. From April 7 to December 31, 1945, the Universal jeep was driven a total of 11,707 miles for all operations. As the Universal jeep was more comfortable than the military jeep it was used as a general utility vehicle more than the military jeep. Records were kept of the fuel consumption of both the Universal and military jeeps involving a total of over 4,000 miles over paved roads with no load. At speeds of 20 to 30 miles per hour both jeeps averaged 20 miles per g gallon of fuel, (Table 5). As the speed was increased the fuel consumption __........_._....._-‘i_._...1._v..;. 44.1A;1~@A»p~_ -4‘4|4 ._.._ l__._ _ _4.\> _._.~r..r_.._ .......\....~mn............_,. ... L4 4A“... THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION l 15 Table 5. Fuel Consumption Over Highway—No Load Total ‘Average Kind of Number Wheel Engine Average Total fuel miles surface 0f drive temper- miles mlles used per trips ature per hour traveled (gallons) gallon Universal Jeep Pavement... . . . . . 4 2 175 20-30 228 11 .35 2O 1 Pavement... . . . . . 8 2 170 30-40 732 38 25 19 1 ’ Pavement... . . . . . 11 2 170 40-50 2696 151 5O 17 8 ' Dirt (dry) . . . . . .. 3 2 175 30-40 222 . 15 3 1 Mud . . . . . . . . . . . . 2 2 175 20-30 138 10.80 12 4 Pavement. .. . . . . . 1 2 170 20 20 1.00 20.0 k Pavement . . . . . . . . 3 2 175 30-40 250 14. l0 17.7 Pavement . . . . . . . . 1 2 175 40-50 453 27 .00 16.8 Mud . . . . . . . . . . . . 1 2 175 15-35 36 2.50 14.4 increased. At high speeds of 40 to 50 miles per hour the Universal jeep averaged 17.8 miles per gallon of fuel while the military jeep averaged 16.8 miles per gallon. At normal speeds of 30 to 40 miles per hour the average per gallon was 19.1 miles for the Universal jeep and 17.7 miles for the military jeep. j 0n dry dirt roads the Universal jeep averaged 15.3 miles per gallon of 1 fuel at speeds of 30 to 40 miles per hour. When driving o-ver very muddy roads only 12.4 miles was obtained for Fieach gallon of fuel consumed by the Universal jeep and 14.4 miles per >gallon by the military jeep. The military jeep consumed slightly more l fuel at the various speeds on pavement but less fuel in mud. The trip in 1' mud with the military jeep was partly over roads that had stretches of i firm roadbed. This, of course, would not require as much fuel. Table 6 shows. the average fuel consumption in miles per gallon when i; the jeeps were used to pull trailer loads ranging from 1,250 to 9,727 fpounds over paved roads. With the recommended trailer load of approxi- mately 4,000 pounds at speeds of 35 to 40 miles per hour, the Universal f-jeep traveled an average of 14.5 miles per gallon of fuel. Increasing the i load correspondingly increased the fuel consumption. A Table 7 shows the average fuel used for various field operations. Where pa 7-foot rotary hoe was operated with the Universal jeep, the fuel used [was only .13 of a gallon per acre as compared to .45 of a gallon per acre where a 6-foot tandem disk harrow was operated. Where a one-row cotton Tphopper was pulled at a relatively slow speed .93 of a gallon per acre was fused. Table 7 also shows the fuel consumption of the military jeep for “similar field operations. Hardy? states that “the fuel economy of the jeep as a tractor is low ’ 2E. A. Hardy, Test of the Jeep as’ a Farm Tractor, mimeograph report, University of '¢ atchewan, 1945. Table 6. Fuel Consumption O.vei' Highway With Load _ _ _ Average Total load Miles Total fuel Average Kind of surface Numher Wheel drive Engine miles pulled traveled used miles per of trips temperature per hour (pounds) per trip (gallons) gallon Universal Jeep Pavement . . . . . . . . . . . . . . . . . . . 1 2 180 30-35 3820 296 24 .0 12 .3* Pavement . . . . . . . . . . . . . . . . . . . 1 2 180-190 35-40 4025 305 ' 21.0 14.5 Pavement . . . . . . . . . . . . . . . . . . . 4 2 175-185 25-30 6000 221‘ 1 .4 7.9 ' Pavement . . . . . . . . . . . . . . . . . . . 1 2 185-195 22 9727 11 1 .5 7 .3 Pavement . . . . . . . . . . . . . . . . . . . 1 2 175 30-45 1500 373 ' 22.0 17 .0 Pavement and field . . . . . . . . .. 4 2 185 25-30 6900 7 .9 7.8 Military Jeep Pavement . . . . . . . . . . . . . . . . . . . 1 2 170-180 20-35 1250 300 21 .0 14.3 Pavement . . . . . . . . . . . . . . . . . . . 1 2 180-190 20-35 1500 297 21 .0 14 .1 Pavement . . . . . . . . . . . . . . . . . . . 1 2 175 20-35 1500 74 5.0 14.8 Pavement . . . . . . . . . . . . . . . . . . . 1 2 190 20 5800 11 l .5 14.7 Pavement . . . . . . . . . . . . . . . . . . . 1 4 190 15-20 9000 l1 1 .6 13.8 *Drivin into headwind of 30-35 miles per ho_ur. _ _ _ TOne-ha fof round trip of 22 miles made pulling empty trailer weighing 1500 lbs. at 30 to 35 miles per hour. NOLLVLS LNEIWIHEIdXEI "IVHILIFIHOIHDV SVXELL ‘6L9 'ON NLLEYYIIIH Table 7. Fuel Consumption in Field Work Type and Acres No. of Rate of Engine Fuel G315- Kind of work size 0f covered hours Miles travel Type 0f Drawbar Axle temper- used per tool per hr. operated traveled (M.P.H.) soil pull drive ature (gallons) acre Universal Jeep Disking . . . . . . . . . . . 6' tandem harrow 3 .3 1 .50 6.6 2%—3 sandy _ loam 1150 4 185 2.25 .45 Disking . . . . . . . . . .. 6’ tandem harrow 2.5 6.00 25.7 21/2-3 sandy _ loam 1150 4 190-200 6.60 .44 Rotary hoeing. . . . . two-row . . . . . . . . . 7.5 .67 6.5 10 sandy _ _ loam 425 4 180 .63 .13 Harrowing. . .. . . . . . two-section . . . . . . 2.5 2.00 6.0 3 sandy , _ loam 350 4 170 .75 .15 Chopping cotton. . . one-row . . . . . . . . . 1 .2 3 .00 10.0 3—4 sandy _ loam . . . . . . . . . 4 170 3.25 .93 Seeding . . . . . . . . . . . 18-hole grain drill 3.3 5.00 16.0 3—4 sandy _ . loam 625 4 170 .25 .38 Plowing . . . . . . . . . . . two 14-in. bottoms . . . . . . . . . .10 . . . . . . . . . 2 L6 sandy _ loam 1400 4 180 . . . . . . . . . . . . . . . . Baling hay . . . . . . . . Pick-up} . . . . . . . . 4 .0 1 .00 3 . 6 3 clay . . . . . . . . . 4 180 1 .00 .25 Military Jeep Land rolling . . . . . . . 8-foot . . . . . . . . . . . 2.7 .75 3.5 3-5 clay . . . . . . . . . 4 175 . . . . . . . . . . . . . . . . St_alk_ cutting . . . . . . 2-row . . . . . . . . . . . 3.3 3.00 13 .0 3-5 clay . . . . . . . . . 4 170-180 . . . . . . . . . . . . . . . . Disk1ng_ . . . . . . . . . . . single ... . . . .. 3.3 .60 2.5 3—4 clay 425 4 170 . . . . . . . . . . . . . . .. Harrowing . . . . . . . . . spike two-section. 2.0 1 .00 4.0 3-4 sandy _ loam 425 4 170 .55 .28 Harrowing. . .. . . . . . weighted spike two-section. . . . . 1 .20 3.5 3-4 sandy _ _ _ loam 625 4 180-200 .59 . 30 Seeding . . . . . . . . . . . grain drill . . . . . . . 4 .0 .25 1 .0 3-4 clay 400 4 175 .26 .26 LI NOLLVLHOJSNVHL (INV HEIMOJ d0 EIOHIIOS V SV dHEIf EIHJ. 18 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION Table 8. Fuel Consumption in Belt Work for Universal Jeep Engine Pulley Fuel Fuel used Kind of work Hours temper- speed used per hour operated ature (R. P. M) (gallons) (gallons) Extracting cotton . . . . . . . . . . . . . . . 4.00 165 700 2.25 .56 Filling silo . . . . . . . . . . . . . . . . . . . . . 2.50 180-190 1300 2.25 .90 Feed grinding . . . . . . . . . . . . . . . . . . 1.25 180-190 1600 4.00 3 .20 compared to the small tractors. The average economy for the light small tractor is 2.29 cents per horsepower hour and that for the jeep is 4.2 cents per horsepower hour, or 1.75 times that of the average small tractor.” Table 8 shows the fuel consumption of the Universal jeep when used in belt Work such as operating a silage cutter and feed grinder. These data show that the fuel consumed varies with the RPM of the pulley and, of course, the RPM of the engine. Octane Rating of gasoline used: In all tests with the jeeps regular gasoline was used. The specifications obtained from the manufacturer were CFRSTM 70 octane. ' The Jeep as a Tractor The Universal and military jeeps were both used as a tractor to perform field operations such as, disking, harrowing, seeding, rotary hoeing, chop- ping cotton, baling hay and pulling of loaded trailers. Dishing: The Universal jeep was used to pull a 7-foot 28-disk, tractor tandem disk harrow‘ in disking approximately 20 acres of sandy loam soil. The field had been flat broken and disk harrowed previously, but a light rain had occurred since the last disking. Therefore, the soil was rather loose and fairly dry. Under these conditions the gangs could only be slightly angled to prevent overloading the jeep. The ground was quite rough, which caused the vehicle to pitch; this in turn affected the func- tioning of the governor; this caused the engine to surge as in the case of a tractor operating over rough ground where the load is not uniform. The drawbar pull was 1,150 pounds (Table 7) even with the gangs slightly angled. Therefore, the jeep was overloaded by 250 pounds. On the day the temperature was 79 degrees and the temperature of the jeep engine ranged at times up to 190 degrees. On the day the temperature reached 90 degrees a strong breeze was blowing, yet the engine temperature at times went above 200 degrees. After the ignition was cut off the engine . would continue to fire for a few seconds. The governor was at maximum speed, or the 9th notch, and the throttle almost to maximum. Therefore, the engine was operating at a high speed. When operating over soft ground at maximum loads it was evident that there was considerable wheel slippage. A test was made to determine THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 19 Fig. 4. The military jeep pulling a slightly angled tandem disk harrow. the influence of high and 10W air pressure in distance traveled. With r32 pounds air pressure in the tires 16 trips were made, or 3.75 miles Was traveled, in the fieldin 4O minutes. With 20 pounds pressure 18 trips were made, or 4.25 miles traveled, in 35 minutes. The setting of the governor ithrottle and disk harrow were the same for both tests. This is in line with factory recommendations that for field work the air pressure of the tires be reduced to 18 to 20 pounds. v The military jeep could pull a slightly angled 5-foot tractor tandem ‘disk harrow (Fig. 4) only a short while before the engine became over- Fig. 5. The military (top) and Universal (bottom) jeeps pulling a two-sectio-n spike tooth barrow. 20 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION heated. It could, however, pull a single two-gang disk harrow under normal p conditions. With either jeep pulling disk harrows the operating performance did , not compare favorably with that of a tractor. H amrowing : soil was 325 to 350 pounds. If the harrow were weighted with some 200 pounds the pull ranged around 625 pounds. * pull a two-section harrow satisfac- torily, but the military jeep’s engine overheated when pulling a weighted harrow. either jeep. Plowing: Factory representatives state that the Universal jeep has suf- ficient power to pull two 12-inch mold- board plow bottoms. Such a plow was not available for tests at the Texas Station but to get some idea general operation, ‘the with two 14-inch general purpose bot- toms (Fig. 6). The land was quite weedy and the soil a little too dry for good plowing condition. Under these conditions the draw- bar pull was approximately 1,400 pounds, which was considerably more than the recommended maximum pull of 1,200 pounds. Because the jeep was overloaded only a few rounds were made. - ‘ Fig. 6. The Universal jeep hitched to a plow equipped with two 14-inch general purpose plow bottoms. The drawbar pull was 1400 pounds which was an overload for the jeep. (Spike and spring tooth). Fig. 5 shows both the Universal and military jeeps pulling a two-section spike tooth harrow. The average i drawbar pull of a two-section spike tooth harrow over freshly plowed a The Universal jeep could e When using a spring tooth harrow é only two sections could be pulled by ' of the maneuverability, hitching and a jeep was 1 hitched to a tractor plow equipped v 3 It was found that the “land” wheels of the jeep "slipped excessively on I the green succulent vegetation. The maneuverability was poor on irregular shaped areas. The jeep operator could not reach the plow levers to adjust the plow from the jeep seat. Long plow levers interfered with turning.. The draft of the plow out of the ground was enough to prevent the jeep’s turning within the minimum turning radius of 18 feet over plowed ground. When plowing is done with a small plow, under favorable soil type and moisture conditions and in lands where turn-s can be made across headlands i many of the above difficulties would beueliminated. THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 21 Fig. 7. Jeeps pulling rice drills. Top—The military jeep pulling a 16-7 fertilizer drill. Bottom—The Universal jeep pulling an 18-7 fertilizer drill. Seeding With Grain Drill: The Universal jeep was used to- pull an 418-7 fertilizer rice drill to seed 16.5 acres of rice on the farm of H. M. . Cole near Beaumont, April 11, 1945 (Fig. 7). The sandy soil had been "plowed, disk harrowed and freshly harrowed with a spring tooth harrow. iThe drawbar pull of the drill with seed and fertilizer hoppers full was i625 pounds (Table 7 ). The jeep pulled the drill under these conditions at some 3 to 4 miles per hour with a normal engine temperature of 170 7 degrees. When drilling over the freshly harrowed soil without a plank drag iattached to the drill it was difficult to distinguish the wheel track of the drill so that the drilled areas would not be overlapped or undrilled areas "be left. The military jeep was not used to pull the 18-7 fertilizer rice drill as p it had previously been tried for pulling a 16-7 fertilizer rice drill (Fig. 7). ~ It had also been determine-d that the engine would overheat when pulling adrawbar pull of 625 pounds in loose freshly harrowed soil. g In seeding rice it is common practice to attach a plank drag (3 or 4 ‘ i planks wide) behind the drill to compact the soil about the seed. The drag 22 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION Fig. 8. The military jeep pulling a solid concrete roller weighing approxi- mately 6,000 pounds over fairly firm soil. The drawbar pull was 750 pounds. On soft freshly disked land the pull will be much more. could not be used when the jeep was used to pull the drill. In seeding oats, wheat and other small grains such a drag is not generally used. As the drag could not be pulled in combination with the drill the drag was pulled over the field by a tractor. Land rolling: The military jeep was used to pull a double gang soil pulverizer weighing approximately 1,000 pounds over about two acres of bedded land. As the roller sections turned freely the draft of the machine was low and it could be pulled easily With the jeep. On bedded or ridged land, the ridges spaced 38 to 42 inches apart caused the wheels to “ride” up on the sides of the ridges as the Fig. 9. The Universal (top) and military (bottom) jeeps pulling a rotary hoe to culti- vate young corn. 500 pounds. At speeds of 10 miles per hour the drawbar pull was 400 to E THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 23 ifdistance between the wheels of the jeep is 481A. inches. Trouble of this §type would not be encountered when operating on flat land. Fig. 8 shows a solid concrete homemade land roller weighing approxi- gmately 6,000 pounds being pulled over fairly firm soil with the military jeep. Under these conditions the drawbar pull was 750 pounds. When éused over freshly harrowed soil the pull would no doubt be more and this type of roller would be too heavy to be pulled with a jeep. ’ Rotary hoe: Fig. 9 shows the Universal and military jeeps pulling a 7-foot rotary hoe over young corn. The rotary hoe was also pulled over lseveral acres of young cotton two different times between emergence of seedlings and thinning with good results. When used on the young corn the hoe was pulled at about 10 miles per hour with a drawbar pull between £2400 and 500 pounds. In using the jeeps to pull the rotary hoe over crops where» the rows were spaced 36 to 4O inches apart the wheels came within a few inches of the rows on each side of the vehicle. Therefore, it was necessary to drive carefully to prevent driving over a row of plants. Mechanical chopping of cotton: Fig. 10 shows the Universal jeep pulling _ a one-row mechanical cotton chopper. ; The jeep could have pulled a two-_ _ row chopper with ease. The only trouble would be the track or width of the jeep not fitting the row spacing, and that of keeping the chopper on the row all the way to the end, and §getting the chopper lined up with the rows for the return trip. j Balmg hay‘. The Universal jeep Fig. 10. The Universal jeep pulling a sin- shown pulling a small two-man gigifgwpsfittgnfgggggfi- cfiipfgld pick-up hay baler in Fig. 11. The ' ' ',"""*"lifl""l"w""a1"vr'r-*~ mww w w .- ~» “ww- - Fig. 11. The Universal jeep pulling a small pick-up hay baler. A total of 100 bales of hay were baled in one hour. 24 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION jeep was used to pull this baler for about one hour during which time; about 100 bales of hay were baled. The pulling of the hay press was very light load, but there was considerable weight of the baler carried on the rear end of the jeep. The windrows were somewhat crooked and extra care had t0 be exercised in driving the jeep to keep the pick-u reel in line with the windrow. Raking hay: The military jeep was used to pull a side delivery hay rake for about one hour. In the beginning, the rake was pulled with the transmission in first gear and the transfer case in low range. After about 1 15 minutes, the transmission was shifted into second gear, the transfer‘ case remaining in low range, and the vehicle was driven at a speed of’; about 15 miles per hour. The temperature of the engine ranged from 190 5 to 200 degrees depending on whether the travel was toward or with the ,:_ wind. Stalk cutting: Fig. 3—left shows the military jeep pulling a two-row tractor type stalk cutter cutting cotton stalks, and Fig. 3—right shows . the Universal jeep pulling a four-row homemade cutter over sorghum stubble. The jeeps had ample power to pull either the two- or four-row i stalk cutters in fields dry enough that soil would not stick to the cutter ~ blade.’ The cutters could be pulled at desirable speeds. The average tricycle or general purpose row-crop tractor straddles two » rows with the rear wheels, while the front wheel is in the middle between j the rows. With this arrangement two- and four-row stalk cutters can be hitched to the center of the power and the cutters will be in correct a position to cut the rows of stalks. As the jeep straddles only one row with 1 the wheels in the middles on each side it is necessary to hitch the cutters as far to the side as possible on the jeep drawbar as explained above under hitches. Even though there is a screen in front of the radiator to prevent trash '7 collecting on the radiator grill trash will collect on the screen to such an extent that the cooling of the engine is affected. Consequently, when operating under such conditions frequent inspections of the screen are necessary. Pulling trailers: Both the Universal and military jeeps were used to pull trailers in the field in connection with the harvesting of cotton, grain sorghum, rice, corn and hay. They were also used to pull trailers loaded with fuel oil and other supplies needed in servicing other farm equipment. Fig. 12, bottom, shows the jeeps pulling four-wheel trailers in the field to handle grain from combines harvesting grain sorghum. The jeeps could easily pull loads of 6,000 pounds in dry fields. In harvesting corn, cotton and hay the jeeps did a satisfactory job of pulling two- and four-wheel trailers in the field and from the field to the barn or to the gin (Fig. 13). THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 25 When pulling loads over row crop land where there are ridges it is best to travel parallel or at an oblique angle to the ridges rather than straight across or at a right angle to the ridges, because in the latter case the 120-inch wheel base of the jeep make-s the front and rear wheels drop in the depressions between the ridges or rise over the ridges at the same time. Such a condition makes rough riding and gives intermittent heavy and light pulling, causing severe jerking of the load. j The jeep can handle fairly heavy loaded trailers on land where small i grain has been sowed with a grain drill and on hay land. To pullrice carts from the combine- to trucks parked on roadways it is necessary that the field be dry enough to be firm, and that soft areas be avoided (Fig. 14). {Moving equipment: The jeep is an excellent source of power for trans- ferring or shifting equipment from barn to field, or vice versa, and from Fig. 12. Jeeps pulling trailers. Top—The Universal jeep (in front) pulling a four-wheel trailer loaded with a knocked-down grain dryer, and the military jeep pulling a two-wheel trailer loaded with miscellaneous equipment. Bottom—Both jeeps pulling four-wheel trailers loaded with milo from the field. 26 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION Fig. 13. Jeeps are excellent sources of power for pulling two-wheel trailers. one field location to another. Plows, grain drills, hay tools, pull type corn pickers and other pull type equipment can be moved rapidly from place to place with the jeep. For example, the jeep was used to pull a two-row pull type corn picker from the College campus over the highway, across a one-way river bridge and into the field, a distance of approximately 10 miles in a much shorter time than it could have been done with a tractor. Belt work: Fig. 15 ‘shows the Universal jeep operating an ensilage cutter and a feed grinder. The jeep was used on August 1 to operate a medium sized ensilage cutter. During 2% hours of operation, approximately 10 tons of silage were cut and blown about 35 feet high into a silo. The governor was in "“"v'"'-"‘ ‘ "r" ‘i’ r W. “"‘+".“""‘v"""“"'l'f'~"":"“i'l"~wfi1'?'w ~ OF POWER AND TRANSPORTATION 27 THE JEEP AS A SOURCE . . . . . . .\. Fig. 14. Universal jeep used to pull rice cart (top) and trailer (bottom) to handle grain from combines in the field. 5th position and the throttle in 2nd position. At this setting-the RPM of the 8-inch pulley ranged between 1270 and 1300. The speed of the ensilage cutter ranged between 640 and 650 RPM. The maximum air temperature on August 1 was 100 degrees F. In oper- ating between 2:00 and 3:00 o’clock in the afternoon, the temperature of the jeep engine went up to 190 degrees. When the hood over the engine was raised the temperature of the engine dropped to 185 degrees. Other than the heating of the engine no trouble was encountered in operating the ensilage cutter. On November 7 the jeep was used to operate a roughage feed mill and grinder. The governor was set in 9th position and the throttle in 4th position. The RPM of the jeep pulley was approximately 1,500. The air temperature was 70 degrees. Under these conditions the engine heated to 185 degrees with the hood down and 180 degrees with the hood up. About ‘é ton of dry alfalfa hay was chopped in 47 minutes and 1 ton of milo ground in 38 minutes. The jeep was also used to operate a cotton bur extractor for 4 hours. BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION Fig. 15. The Universal jeep used for belt work. Top-Jeep furnishing power to oper- é ate feed mill to chop dry p hay and to grind milo. Bott0m—Jeep furnishing f power to operate ensilage= cutter. As it was nece-ssary to operate the extractor very slowly, about 150 RPM, the governor was set in_2nd position and the throttle in 3rd position. These settings gave a pulley speed of 800 RPM. At this speed the engine temperature was 150 degrees. Th air temperature was 68 to 70 degrees. In all operations the transmission was in high gear. l THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 29 The Jeep as a Truck The rear springs of the jeep are designed to carry a normal load of 800 pounds with an average of 190 p pounds deflection rate per inch at 1A, ’ camber. The body space for carry- ing of pick-up loads is 40 inches from seat to tail gate. The tail gate pro- ‘vides a 14% inch extension. The Width of'the body at the floor is 30 inches. Bench like fenders give an additional width of 10% inches on each side or a total inside body width of 51s inches. These bench fenders may also serve as seats. _ _ 16. The Universal jeep used as a The capacity of the pick-up body truck to haul a large fan weigh- ‘on the Universal jeep is much less ing “M” 725 pmmds‘ Fig. 17. Top—Universal jeep used to pull trailer load of cotton over highway to gin. Bottom—Universal jeep and tractor at gin with trailer loads of cotton. 30 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION than the average ton pick-up truck. Six 10-gallon milk cans can y: carried in the 30 by 40 inch pick-up bed of the Universal jeep. If t, passenger seat is removed, nine 10-gallon cans can be hauled. Fig. 16 shows the Universal jeep hauling a large fan weighing pounds. The rear section of the top had to be taken oif to permit loadi of the fan as it extended above the top as shown in Figure 16. I Even though the jeep does not have the body capacity of the pick-l truck additional loads can be transported easily on trailers pulled by t jeep, both in the field and over the road (Fig. 17). - , 1 The Jeep as an Automobile Due to the short wheel base and stiff springs the riding comfort of i jeep does not compare with that of an automobile or pick-up truck. spring cushions provided for the seats of the Universal jeep make l, model more comfortable than the military‘ jeep. Several long trips were made ranging from 200 to 500 miles, using jeep as an automobile. These trips were made in one day with individuals taking turns at driving, without each being unduly tired at th end of the trip. I The jeep makes a very good vehicle for short trips about the farm o ranch and for making quick trips to town. Fig. 18 shows the jeep bei use-d to check on a crew throwing up levees in rice fields. Fig. 19 sho a farmer and visitors following hay harvesting equipment in the field. » Fig. 18. The Universal jeep makes an excellent means of transportation to check field operations diflicult to get to with regular automotive equipment. THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 31 The Jeep as a General Utility Vehicle During the time the jeeps were being tested, both the Universal and iijmilitary models were used extensively as general utility vehicles about ithe farm and ranch, much like the average family would use them. The jeep on the fa/rm: After observing the performance of the jeep in connection with rice farming, R. H. Wyche, superintendent of the Texas Agricultural Experiment Substation at Beaumont, stated, “The jeep would §Lbe useful in rice farming as it can get around in places that are too wet for a pick-up truck and will cross levees that cannot be crossed with a Qtruck. It could also be used for trips to town for repairs and supplies. a In some cases farmers carry a horse to the field in a trailer pulled by a p“ truck. The jeep can do this and go places Where the truck cannot go.” The jeep would also be useful in pulling trailers that are used for hauling fuel and seed to tractors, drills, and harvesting equipment. The jeep proved to be useful in connection with cotton farming. Several trips were made about cotton fields and plantations when road-s were so muddy that no other automotive equipment could get over the roads. Supplies of fuel and seed can be delivered by trailer to tractors and planters and other equipment in the field. At harvest time, many farmers, especially in the northwestern part of Texas, use their trucks, cars, and tractors to pull trailer loads of cotton out of the field and over the highway to the gin (Fig. 17). This could be done easily with a jeep. While har- {m-qWW»-- Qvzavq-vry . . Fig. 19. A farmer with visitors using military jeep to inspect hay harvesting equipment. vesting cotton near Lubbock several quick trips for repairs were made to blacksmith shops 3 or 4 miles distance. Generally, farmers who saw the jeep perform about the farm felt that it would be very useful as a general utility vehicle, but visualized the jeep as a substitute for the tractor in farming operations only in an emergency. ‘ The jeep on the ranch: The jeep makes a very good general utility vehicle about the ranch as it can get about over rough terrain, carry U2 BULLETIN NO. 679. TEXAS AGRICULTURAL EXPERIMENT STATION x RC ~. x‘ Q m Fig. 20. Top-—Military jeep used to inspect cattle on the range several miles from headquarters. Bottom—-Ranchmen using jeep to travel over rough trails. THE JEEP AS A SOURCE OF POWER AND TRANSPORTATION 33 isupplies to distant sections of the ranch, pull trailers, and in many cases ibe used as a substitute for the saddle horse as shown in Fig. 20—t0p. _ On the Texas Agricultural Experiment Substation near Sonora, ranch Eboundary fences of a section of land were inspected where it was necessary gto travel over rock strewn ground covered in places with thick brush in less than an hour. If necessary, a few posts, a spool of barbed wire and iessential repair tools could have been carried along in the jeep. At another iilocation, all fences and livestock were inspected in 30 minutes where a iiordinarily it would have required 2% to 3 hours on a horse. In rough country, the jeep was easily driven over a trail that wound éamong thorny brush, prickly pear, over rocks, down and across gulleys iwhere a ranchman would try driving a truck only once (Fig. 20—bottom). iThe jeep was driven up a mountain trail that appeared to be used only for downhill travel with caution by local ranchmen. The jeep was used to pull supply trailers and special horse trailers as shown in Fig. 21. It was also found that with the top and windshield down the jeep would make an excellent hunting vehicle. ‘ '"'!"yfflwwfmy:gwwwqwpnfrff"@vwwvwawvygwg~wpww .. u- — 5m ww- reg-wry’ Fig. 21. Military jeep being used to pull horse (top) and supply (bottom) trailers. 34 BULLETIN NO. 679, TEXAS AGRICULTURAL EXPERIMENT STATION Acknowledgments The author is indebted to W. E. McCune, R. H. Wyche, and W. H.’ ' Dameron for their assistance in making these tests. Thanks are due also to L. C. Hudson, service representative of the‘. Willys-Overland Motors, Inc., for his work in maintaining the jeeps during , the tests. Summary and Conclusions The data presented in this bulletin give results of tests to determine the adaptability of the jeep as a source of power on the farms and ranches in Texas. A “Universal” or peacetime model jeep, equipped with power take-ofi, belt pulley, governor and other accessories, was furnished by the Willys- Overland Motors, Inc. The War Food Administration arranged with the Army for the release p of a “military” model jeep for test purposes. Where possible both models were tested on the same kind of work. The Universal model was capable of pulling heavier loads than the military model because the gear ratios for the former were reduced in the transmission, transfer case and axle. The clearance at the axles of 8% inches was adequate for road, ranch A and field work in harvesting broadcast crops but not enough for the late cultivation of cotton, corn and other row crops. The trailer hitch on the military model was not suitable for use of farm . trailers and implements. A drawbar hitch for farm implements had to be constructed and attached to the military jeep. The hitch and drawbar on the Universal model are adequate for most implements but drawbar extensions must be made when hitching to power take-off equipment. Maneuverability of the jeep in the field does not compare favorably with i‘ the ordinary farm tractor. When pulling heavy loads the cooling system of both models was not v of sufficient capacity to prevent the engine from heating excessively. Fuel consumption for travel over highways compared favorably with the regular pick-up truck. Fuel consumption for heavy field work was considered high. For field work the jeep did not compare favorably with the tractor. As a truck, the jeep was an excellent source of power for pulling trailer loads of produce from farm to market and supplies to the farm, and for odd jobs about the farm, but it did not compare favorably in capacity _ with the pick-up truck for hauling. As an automobile, the comforts of the jeep were not comparable to those of an automobile. The jeep, however, makes an excellent utility vehicle for doing various chores about the farm and ranch. THE JEEP AS A SOURCE OF POWER AND TRANSP-ORTATION 35 Fig. 22. The jeep cannot go everywhere. An attempt was made to cross a drainage ditch on a rice farm. The soft mud in the ditch was too deep and the jeep sank to where the tops of the front wheels were almost covered.